As an example of a conventionally known vehicle door, there are a hinge door and a slide door (for example, refer to Japanese Unexamined Patent Publication No. 2001-1756). An example of a conventional hinge door is described with reference to FIG. 9.
The vehicle door 1 comprises a door panel unit and a door module. The door panel unit comprises an outer panel 13 forming an outer wall of the door 1, a hinge member 1a for attaching the door 1 to the vehicle body, and an inner panel provided at a vehicle inner circumferential edge of the outer panel 13.
On the other hand, a frame structure forming the framework of the door module comprises a front sash 6a positioned at a vehicle front side, a rear sash 6b positioned at a vehicle rear side, an upper sash 6c positioned at the highest portion of the door module, a middle frame 6d that is positioned below the upper sash 6c and extends horizontally, and a window 5 enclosed by these sashes, and further comprises a panel 3 including a lower frame 6e positioned at the lowest portion of the middle frame 6d and door module and a space 4 therebetween. The upper sash 6c is along an upper edge 10a of the door glass 10.
The frame structure comprises a drive unit 20 for driving the glass plate up and down, a door latch mechanism, and a latching operation mechanism (door inside handle).
The sashes 6a, 6b, and 6c, drive unit 20, and door glass 10 compose a door glass lifting and lowering device.
As shown in FIG. 9, the drive unit 20 comprises a steel-made base plate (referred to as a base panel, also) 21 provided between the middle frame 6d and lower frame 6e, and a pair of front and rear frames 22 and 23 that are fixed on the base plate 21 and extend vertically. Upper ends and lower ends of the frames 22 and 23 are fixed to the middle frame 6d and the lower frame 6e. Upper pulleys 26 and 28 and lower pulleys 27 and 29 are provided at the upper ends and lower ends of the frames 22 and 23. Furthermore, a drive pulley 25 and a motor 24 for rotating the drive pulley 25 are provided on the base plate 21. This motor 24 is a motor with a reduction gear, which uses an on-vehicle battery (not shown) as a power supply and is rotatable forward and backward.
A wire called a wire cable is set on these pulleys so as to cross over in an X shape. Namely, this wire comprises a front moving portion 31a laid vertically across the front side upper pulley 26 and lower pulley 27, a rear moving portion 31b laid vertically across the rear side upper pulley 28 and lower pulley 29, a first slanting portion 31c slantingly laid across the upper pulley 28 and drive pulley 25, a second slanting portion 31d slantingly laid across the lower pulley 27 and drive pulley 25, and a third slanting portion 31e slantingly laid across the upper pulley 26 and lower pulley 29.
The first and second slanting portions 31c and 31d and the third slanting portions 31e cross each other in an X shape. For the first slanting portion 31c and second slanting portion 31e, tension member 30 for absorbing the elongation and slack of the wire by appropriately tensioning the entire wire.
At the vertical middle portions of the front moving portion 31a and rear moving portion 31b, a carrier plate 38 for supporting the door glass 10 is fixed so as to be almost horizontal. A U-shaped glass receiving member 41 is fixed to the carrier plate 38.
As a means for fixing the wire 31a to the carrier plate 38, as shown in FIG. 9(B) and FIG. 9(C), the wire 31a is inserted into a hole made at a carrier plate attaching location 39, and fixed by means of an optional method such as caulking.
The end portion of the first slanting portion 31c is latched on the drive pulley 25, and a length that allows the lifting and lowering stroke of the door glass 10 is wound around the drive pulley 25. The end portion of the second slanting portion 31d is also latched on the drive pulley 25, and the length that allows the lifting and lowering stroke of the door glass 10 is wound in a multi-round spiral groove 25a of the drive pulley 25.
Therefore, when the drive pulley 25 rotates clockwise, the first slanting portion 31c of the wire is extended from the drive pulley 25, and the second slanting portion 31d is wound by the drive pulley 25, and the moving portions 31a and 31b simultaneously rise. In accordance with this rise, the carrier plate 38 and door glass 10 lower together. Furthermore, when the drive pulley 25 rotates counterclockwise, the first and second slanting portions and the moving portions move oppositely to each other, whereby the carrier plate 38 and door glass 10 rise.
Next, the well-known tension member shown in FIG. 10 (referred to as a tensioner, also) is described in detail. The tensioner 30 comprises a swing member 60, a first slide member 61, and a second slide member 62. These members are, as generally known, integrally plastically formed from a synthetic resin such as nylon or polyacetal which enables easy sliding but does not allow the occurrence of sliding noises.
The swing member 60 integrally connects the first slide member 61 and second slide member 62 while leaving a gap 63 that serves as a passage for the wire 33 therebetween. The swing member 60 is pivotally attached to the base panel 21 so that pendulum-like horizontal reciprocative movements of the second slide member 62 of the tensioner 30 are possible. A fixing hole 65 is formed in the base panel 21, a through hole 66 is formed in a hollow portion 61d in the first slide member 61, and a pivot 64 is formed of a caulking pin for pivotally attaching the first slide member 61 to the base panel 21.
A wound spring 70 is housed in a hollow portion 61e of a lower opening formed in the body of the first slide member 61, one end thereof is inserted and fixed into a spring end fixing hole formed at an upper side of the body, an other end is inserted and fixed into a spring end fixing hole formed in the base panel 21, and the wound spring is constructed so as to absorb the slack that may be generated from the wire 33 by always pressing the second slide member, 62 in one direction.
Circumferential surfaces opposed to the wire 33 passing through the wire passage 63 between the first slide member 61 and second slide member 62 are shaped as shown in the figure so as to have U-shaped sections opening outward. These first slide surface 61a and second slide surface 62a which have U-shaped sections opening outward are provided with brim portions 61b and 62b at both sides to guide the passing wire at a central flat portion.
The first slide member 61 and second slide member 62 are constructed so that, when the wire 33 passes through the wire passage 63 between the first slide member 61 and second slide member 62, the wire reciprocates toward an arrow 90 direction while being always guided by the flat surfaces 61a and 62b formed on the circumferential surfaces of the first slide member 61 and second slide member 62 in a case where the movement locus of the wire 33 advancing and retreating between the drum 25 and pulley 27 deflects in an axial direction (arrow 90 direction) of the drum 25 as shown in FIG. 10 in accordance with the rotation of the drum 25 which has the abovementioned spiral groove 25a. 
In the condition of FIG. 9, as mentioned above, when the drive pulley 25 is rotated clockwise to lower the door glass 10, the second slanting portion 31d of the wire is strongly tensioned, and a slightly slackening condition is applied to the first slanting portion 31c of the wire.
Particularly, when the drive pulley 25 is driven clockwise (counterclockwise) to lower (raise) the door glass 10 via the wire 33, even if the door glass 10 reaches a bottom dead point 10d (top dead point 10c) and stops, the drive pulley 25 continues to slightly rotate, and extends the first slanting portion 31c (second slanting portion 31d) of the wire. In such a condition, the second slide member 62 in the tension member 30 pulls and tensions the first slanting portion 31c (second slanting portion 31d) of the wire that is about to rotate in an arrow 59 direction and slacken, and absorbs the slack.
In the conventional vehicle door, the glass plate 10 is supported by elastic members provided in the grooves of two front and rear sashes 6a and 6b of the window frame when the glass plate has risen halfway or has entirely risen.
Therefore, at a moment at which the door 1 is closed with great force and it hits against the frame edge of the getting in/out section, in both cases of a hinge door and slide door, the glass plate 10 warps toward the inside of the vehicle due to inertia or shifts toward the inside of the vehicle while collapsing the elastic members (blades) in the sashes, and the lower portion of the glass plate 10 comes into contact with the internal components arranged in the space 4 of the panel 3. Thereby, there was a problem that an impact noise occurred.
In order to solve the abovementioned problem, there is a conventional vehicle door 1 constructed so that an additional guide rail is provided at the middle position between the sashes 6a and 6b that are two front and rear guide rails within the panel 3 of the door 1, these three rails support the glass plate 10, and the glass plate 10 moves up and down while being supported by the rails.
With this construction, door stability when it is closed is improved. However, during use, resistive loads of the three rails are applied to upward and downward movements of the glass plate 10. Due to the sliding resistance, upward and downward movements of the glass plate become entirely heavy. Therefore, there is a problem that the drive unit is required to output a high output, so that the drive unit is increased in size.
Furthermore, it becomes necessary to match the third rail with the movement locus of the glass plate. That is, it requires high-level techniques to form a guide surface on the third rail in contact with the movement locus of the glass at the middle position between the two front and rear guide rails in accordance with the movement locus of the glass plate which is determined by the sashes 6a and 6b serving as the two front and rear guide rails in the window frame. This work involves personnel problems such that it becomes necessary to station a specially skilled person at the line of assembly of the door.
Furthermore, if the skill of a worker is poor, the guide surface of the guide rail added at the middle position between the two front and rear guide rails may not match with the movement locus of the glass plate, and when the glass plate is moved up and down, there is a problem that the glass plate may creak or the movement thereof may become heavy or difficult.
Furthermore, in a case where the window 5 of the conventional door is large, the door glass 10 must have dimensions adapted to the window 5. In accordance with this, the moving up and down stroke of the carrier plate 38 supporting the glass must be increased. On the other hand, an interval between the upper and lower pulleys 26 and 27 supporting the wire 31a in the drive unit 20 provided at the panel 3 is set within a limited range in the internal space of the panel 3.
Therefore, when increasing the stroke of the carrier plate 38 between the upper and lower pulleys, the top dead point (bottom dead point) of the carrier plate 38 comes closer to the pulley.
When the carrier plate 38 comes closer to the pulley 26, and in a case where the door is opened and closed, if the lower end of the glass 10 supported by the elastic blades repeatedly deflects toward a vehicle inward direction 73 and a vehicle outward direction 73′ as shown in FIG. 9(C), a bending force with a large angle of bending 56 is repeatedly applied to the fastening point 39 of the wire 31a to the carrier plate 38. Therefore,there is a problem that cutting of the wire 31a at the fastening point 39 occurs.
In order to avoid this problem, a method in which the top dead point (bottom dead point) of the carrier plate 38 is prevented from coming closer to the pulley 26 can be considered, however, in this case, the moving up and down stroke of the carrier plate 38 is further reduced, and it becomes necessary to make the window smaller.
Furthermore, in the conventional vehicle door, the first slide surface 61a and second slide surface 62a of the tension member 30 are formed to be flat as shown in FIG. 10.
Therefore, in response to the rotation of the drum 25 having the abovementioned spiral groove 25a, the movement locus of the wire 33 advancing and retreating between the drum 25 and pulley deflects in the axial direction (arrow 90 direction) of the drum 25, whereby the first slide surface 61a and second slide surface 62a evenly reciprocatively slide toward the axial core direction (in the arrow 90 direction).
Thereby, the slide surfaces are evenly worn, and this makes use possible over an extended period of time.
However, in accordance with increases in the number of upward and downward movements of the glass plate 10 due to a long period of use, the first slide surface 61a and second slide surface 62a may be partially severely worn. In such a case, the worn portions are locally depressed, and the wire 33 that reciprocates in the arrow 90 direction in FIG. 10(B) and FIG. 10(C) is entangled in the depressed portions. Then, in accordance with increases in a depth of the depressions, when the wire slips out depressions, a snapping noise occurs. There is a problem that the driver of the vehicle mistakes the snapping noise for an abnormal noise and becomes concerned.